Hello, I am a developer and I am using the L431RC chip on a custom board. I am using CAN BUS to communicate with the system, and during normal operation (via firmware), there are no communication issues,in fact, everything works quite well.
However, I encountered a major issue when trying to access the bootloader via CAN BUS. Essentially, I have run countless tests, but I never receive any response from the bootloader, and I don’t know why.
I should mention that I have followed the AN2606 and AN3154 documents to interface correctly, I am using the correct pins (PB8 and PB9), a 16MHz HSE, and TIM16 active as described in the files. To enter the bootloader, I use two external buttons, Reset and Boot.
The thing is, I tried accessing the bootloader via UART, and everything works, so the boot circuitry is functioning.
I have two STLINK V3 programmers, a SET and a MOD, but neither receives a response; I even tried connecting directly to the CAN's RX and TX (using the appropriate port) via the SET, but still nothing.
I also tried all of this on an F407, and everything works perfectly there.
Looking at the oscilloscope, I noticed that the L431 does not respond after sending 0x079, there is no ACK code, as if the chip was not enabled for CAN. Does anyone have any idea?
